The present invention relates to a seat recliner mechanism and, more particularly, to an infinitely adjustable linear seat recliner mechanism for positioning and retaining a reclinable seat back relative to a seat cushion in a desired angular position.
Commercial aircraft and motor vehicles are commonly equipped with adjustable seat assemblies which provide added comfort and convenience for the occupant. Typically, seat assemblies include a seat cushion that is affixed to a structural seat frame. The seat frame is mounted to the floor of the vehicle or aircraft and is usually of a rail-type design to allow forward and rearward ("fore and aft") adjustment of the seat cushion. A seat back member is typically coupled for pivotal movement relative to the seat cushion by one or more recliner support members. A seat recliner mechanism provides for angular positioning of the seat back relative to the seat cushion.
In general, recliner mechanisms can be categorized into two basic design categories. The first category typically relies on some type of frictional engagement locking mechanism to set the inclination of the seat back. The second category relies upon an incrementally engagable ("meshed") device. An advantage of frictional engaging recliner mechanisms is that the angular adjustment potential is infinitely variable.
Numerous incrementally engagable seat recliner mechanisms have been disclosed in the art for positioning and retaining the seat back in a fixed angular position relative to the seat cushion. For example, U.S. Pat. No. 4,372,610, issued to A.J. Fisher III, et al on Feb. 8, 1983, describes a recliner mechanism employing a pair of meshing straight-toothed racks. One of the racks is connected to an upper recliner structure through a toothed quadrant component. Adjustment of the reclined angular position of the seat back is accomplished by changing the meshed position of one rack with respect to the other. Such seat recliner mechanisms employ meshing teeth for position fixing which provides stepped finite incremental angular changes in the reclined position.
Likewise, various frictional engagement recliner devices are known in the art. U.S. Pat. Nos. 4,687,252 and 4,705,319, each assigned to the assignee of this application, relate to continuously variable recliner mechanisms employing a toothed sector on the upper recliner structure adapted to mesh with a recliner gear which, in turn, communicates with a rotating actuator clutch drum. A clutch spring is selectively tightened or loosened around the clutch drum to provide the infinitely variable seat back adjustment.
Although the afore-noted "prior art" devices perform satisfactorily, it is desirable to provide further improvements in the design and operation of seat recliner mechanisms. Therefore, it is desirable to provide an improved linear seat recliner mechanism adapted to provide continuously variable seat back angular positioning. In this manner the seat occupant is not constrained to a fixed angular position dictated by a incrementally adjustable recliner mechanism. Likewise, many currently known seat recliner mechanisms produce an annoying clatter or "ratcheting" sound during adjustment. It is therefore desirable to provide a linear seat recliner mechanism which provides silent operation and has smooth release characteristics. Another desirable characteristic for a seat recliner apparatus is the ability to prevent unrestrained pivoting motion of the seat back in the event of failure or improper operation of the seat recliner mechanism. Designers are further constantly striving for ease of production, low cost, simplicity, and reliability of the recliner hardware components.
Accordingly, it is a primary object of the present invention to overcome the disadvantages of the prior art and provide an improved linear seat recliner mechanism. In general, this is accomplished by providing an infinitely adjustable linear seat recliner mechanism and a method of utilization of the same. In a preferred embodiment of this invention, a threaded split nut assembly is adapted to spin on a linearly movable threaded recliner rod. The split nut assembly is encased within a clamp assembly. The clamp assembly has an interior wall surface defining a passage in which the split nut assembly is disposed such that an exterior surface of the split nut assembly engages the interior wall surface of the clamp assembly. The helix angle of the recliner rod is designed to make it fairly easy for the recliner rod to move relative to the rotatable nut assembly. A release lever is provided to pivotally move a release shaft associated with the clamp assembly. Release of the seat back, to allow angular adjustment thereof, is achieved by selectively loosening the clamp assembly whereby the split nut assembly rotates freely on the recliner rod. Therefore, the recliner rod is permitted to move linearly for generating corresponding pivotal adjustment of the seat back. To lock the seat back in a desired reclined position, the clamp assembly is selectively tightened to urge the split nut assembly into locking engagement with the threaded recliner rod thereby lockingly restraining movement of the threaded rod.
An advantage of the present invention is that it is ideally suited for reclining seat assemblies which also have mechanisms to allow the seat back to be pivoted forward allowing ingress to the rear seats in conventional two-door motor vehicles. Furthermore, the present invention is advantageous in that its design is compatible with many recliner seats presently in production. Additionally, the seat recliner mechanism is extremely light and can be placed in a very small space "envelope" under the seat.
Additional objects, benefits, and advantages of the present invention will become apparent to those skilled in the art to which this invention relates from the subsequent description of the preferred embodiments, and the appended claims, taken in conjunction with the accompanying drawings.